Effect of Single-Walled Carbon Nanotubes on <I>Bacillus Anthracis</I> Cell Growth, Sporulation, and Spore Germination

Abstract

In this study, the effect of single-walled carbon nanotubes (SWCNTs) on B. anthracis cell growth, spore formation, and spore germination was studied. We found that SWCNTs at a concentration of 100 microg/ml exhibited obvious antimicrobial activity on 10(6) cfu/ml B. anthracis cells. At 300 microg/ml, 1 h of SWCNTs treatment could inactivate B. anthracis cells by approximately 2 log viable cell reduction. The SWCNT treatment did not induce spore formation. We also found that SWCNTs were not effective in the inactivation of B. anthracis spores at concentrations from 50 microg/ml up to 300 microg/ml. Fluorescence microscopy and scanning electron microscopy were used to examine the interactions between SWCNTs and B. anthracis cells/spores. Analysis of these microscopic images suggested that the direct contact between SWCNTs and B. anthracis cells lead to cell membrane damage and the inactivation of cells, whereas the lack of tight direct contact between SWCNTs and spores was the reason accounting for its ineffectiveness in inactivating spores.

Inhibitory effects of single-walled carbon nanotubes on biofilm formation fromBacillus anthracisspores

“…It is less likely that SWCNTs could directly damage and inactivate bacterial spores as spores possess a highly protective multilayer 'lockbox' coating (Aferchich et al 2012). On the other hand, the results have shown that the presence of SWCNTs reduced the percentage of germinated spores; this may partially account for the inhibition of biofilm formation.…”

Investigation of antimicrobial activity of photothermal therapeutic gold/copper sulfide core/shell nanoparticles to bacterial spores and cells

“…The spore is usually encased in a thick multilayered coat surrounded by the exosporium [19], making the spore the most resistant life form known. In fact, research has demonstrated that B. anthracis spores are much more resistant than their vegetative cell counterparts to a variety of treatments [20]. …”

“…The supernatant was discarded, and the cell pellet was washed three times with sterile deionized (DI) water, nutrient broth, or PBS. The cells were then resuspended in the respective buffers, and diluted to desired concentrations for further experimental use [20]. …”

“…5 μL of the fixed samples were placed on a cover slide and air dried. The dried sample was then coated with gold using Denton Vacuum Desk IV (Czech Republic) as previously described [20], and the SEM images were taken using the FEI XL30 microscope (Netherlands) at the Shared Materials and Instrumentations Facility (SMIF) at Duke University.…”

Superior Antibacterial Activity of Photochemical Synthesized Ag-CNT Composites and their Synergistic Effects in Combination with other Antimicrobial Agents

“…For example, silver nanoparticles (Ag NPs) are one of the metal nanoparticles that have been intensively studied as a bactericidal agent and their utilization is increasing owing to their strong antimicrobial properties and minimal toxicity [5]. Carbon nanotubes (CNTs), especially single-walled CNTs (SWCNTs), are one of the recently discovered antimicrobial agents against a variety of bacterial species [6][7][8][9][10], whereas multiwalled CNTs (MWCNTs) are found little or In use of any of these traditional and newly emerged nanomaterialbased antimicrobial agents, leaching to the environment, soil, the groundwater and transported to surface waters, chemical residues as well as possible aggravated harmful disinfectant byproducts (DBPs) [4], often raise safety and health concerns. In some cases, direct contact with high concentration of antimicrobial agents may cause extensive damage to biological systems (like human tissues) [14].…”